The present invention is directed to a method of sputter-coating substrates with two opposed, two-dimensionally extended surfaces or of manufacturing sputter coated substrates with two opposed, two-dimensionally extended surfaces, also called “plate shaped” substrates. Thereby more than one plate-shaped substrates are continuously rotated around a common axis and, considered in radial direction with respect to the common axis, equally distant from the substrates. The substrates are thus continuously rotated along a common ring-locus around the common axis. The ring-locus has an inner and an outer periphery as well as a center line i.e. a circular locus line centered between the outer and the inner peripheries of the ring-locus.
During their rotational movement around the common axis, the substrates are passed over at least one magnetron sputter source. The magnetron sputter source comprises a stationary magnetron-magnet arrangement and a circular target with a target center and a target center axis and a sputter surface which faces towards the ring-locus. The stationary magnetron magnet-arrangement generates an area of magnetron plasma along the sputter surface of the target.
By establishing, by means of the magnetron magnet-arrangement, a third azimuthal extent of the area of magnetron plasma smaller than the second azimuthal extent between the first and second azimuthal extents according to step c1), the increased azimuthal extent of the circular target towards the target center is taken in account.
Because the stationary magnetron magnet-arrangement only generates an area of magnetron plasma along a restricted area of the sputter surface and net redeposition i.e. of a remaining redeposition in spite of simultaneous sputtering off, especially of a material different from the target material on the target is to be minimized or even avoided, the target is rotated around its center axis and the center of the circular target is covered by the area of magnetron plasma. Thereby the overall sputter surface of the target becomes net redeposited to a minimum or even net sputtered and net redeposition is minimized or even avoided. Additionally, exploitation of the target material is improved.
We understand under the term “net sputtering” and “net redeposition” the balance of simultaneously occurring off-sputtering of material and of redeposition of material.
If sputtering is performed in an atmosphere containing at least one reactive gas, the material deposited on the substrates and which could redeposit on the sputter surface consists of the material sputtered off the sputter surface reacted with the at least one reactive gas. Especially in this case net redeposition is to be minimized or even avoided.
One variant of the method according to the invention comprises establishing the third azimuthal extent of the area of magnetron plasma with respect to the common axis, radially centered between said first and said second azimuthal extents.
One variant of the method according to the invention comprises establishing said third azimuthal extent of said area of magnetron plasma with respect to said common axis, radially aligned with said center line of said ring-locus.
Instead of adjusting the respective azimuthal extents as addressed above under a first approach, under a second approach, the object of the present invention is also resolved, according to the invention, by adjusting the respective averaged strength of the magnetron magnetic field.
This is achieved by a method of sputter-coating substrates with two opposed, two-dimensionally extended surfaces or of manufacturing sputter coated substrates with two opposed two-dimensionally extended surfaces, comprising:
We understand under the term “averaged strength of magnetron magnetic field” closer to the outer periphery, closer to the inner periphery and therebetween, the strength of magnetron magnetic field averaged over the azimuthal extent at the addressed loci along the sputter surface.
One variant of the method according to the invention as just addressed comprises establishing the third averaged strength of magnetron magnetic field at a locus, with respect to the common axis, radially centered between applying the first and the second averaged strengths.
One variant of the method according to the invention as just addressed comprises establishing the third averaged strength of magnetron magnetic field at a locus, with respect to the common axis, radially aligned with the center line of the ring-locus.
One variant of the invention under the first approach, comprises additionally establishing a first averaged strength of magnetron magnetic field, with respect to the common axis, radially closer to the outer periphery of the ring-locus and establishing a second averaged strength of magnetron magnetic field smaller than the first averaged strength of magnetron magnetic field, with respect to the common axis, radially closer to the inner periphery of the ring-locus than to the outer periphery of the ring-locus.
One variant of the variant as just addressed comprises establishing a third averaged strength of magnetron magnetic field, with respect to the common axis, radially between the first averaged strength and the second averaged strength which third averaged strength of magnetron magnetic field being smaller than the second averaged strength of magnetron magnetic field.
One variant of the just addressed variant comprises establishing the third averaged strength of magnetron magnetic field, with respect to the common axis, radially centered between the first averaged strength and the second averaged strength.
Additionally, or alternatively one variant of the method according to the invention comprises establishing the third averaged strength of magnetron magnetic field, with respect to the common axis, radially aligned with the center line of the ring-locus.
The sputter deposition homogeneity along the substrate may be additionally tuned by the variant of the methods according to the invention wherein the sputter surface in new state extends along a sputter surface plane and the magnet pole surfaces of the magnetron magnet arrangement extend along a magnet arrangement plane, the sputter surface plane and the magnet arrangement plane intersecting at an angle α of
0°<α≤20°.
In an alternative variant of the methods according to the invention to the just addressed tilting or additionally thereto the sputter surface in new state extends along a sputter surface plane and a substrate aligned with the sputter source extends along a substrate plane, the sputter surface plane and the substrate plane intersecting at an angle α of
0°<α≤20°.
In an alternative variant of the methods according to the invention to the just addressed tiltings or additionally thereto a target backside extends along a backside plane and magnet pole surfaces of said magnetron magnet arrangement extend along a magnet arrangement plane, the backside plane and the magnet arrangement plane intersecting at an angle α of
0°<α≤20°.
In an alternative variant of the methods according to the invention and to the just addressed tiltings or additionally thereto, a target backside extends along a backside plane and a substrate aligned with said sputter source extends along a substrate plane, the backside plane and the substrate plane intersecting at an angle α of
0°<α≤20°.
In an alternative variant of the methods according to the invention and to the just addressed tiltings or additionally thereto the sputter surface in new state extends along a sputter surface plane and a target backside extends along a backside plane, the backside plane and the sputter surface plane intersecting at an angle α of
0°<α≤20°.
In an alternative variant of the methods according to the invention and to the just addressed tiltings or additionally thereto a substrate aligned with the sputter source extends along a substrate plane and magnet pole surfaces of the magnetron magnet arrangement extend along a magnet arrangement plane, the substrate plane and the magnet arrangement plane intersecting at an angle α of
0°<α≤20°.
Thereby a further variant of the methods according to the invention comprises performing the addressed intersecting along an intersecting line perpendicular to a plane containing the common axis and the target center.
In one variant of the methods according to the invention the addressed angle α is selected to be:
0°<α≤10°.
In one variant of the methods according to the invention, the area of magnetron plasma, referring to the angular position with respect to the target center and with angle zero in outwards direction along a radial line between the common axis and the target center, is tailored as follows:
In one variant of the just addressed variant of the methods according to the invention, the area of magnetron plasma is generated along the periphery of the circular target as a secant starting at an angle in the range of 30° to 50°.
In one variant of the methods according to the invention, in which the substrates are circular, the substrates are respectively drivingly rotated around a substrate center axis which is perpendicular to the opposed two dimensionally extended surfaces.
In one variant of the methods according to the invention, the target center is aligned with the center line of the ring-locus.
In one variant of the methods according to the invention the target is of silicon.
In one variant of the methods according to the invention sputtering is performed from the target in an atmosphere containing at least one reactive gas and a layer of sputtered off material, reacted with the at least one reactive gas, is deposited on the substrates.
In one variant of the methods according to the invention the reactive gas is one of hydrogen and of oxygen.
One variant of the methods according to the invention comprises passing the one of the two two-dimensionally extended surfaces over at least two of the addressed sputter sources.
One variant of the methods according to the invention, comprises passing the one of the two two-dimensionally extended surfaces over at least two of the addressed sputter sources, the targets of the at least two sputter sources being of silicon, performing sputtering from the targets in respective atmospheres containing at least one reactive gas and depositing on the substrates respective layers of sputtered off material, reacted with the at least one reactive gas, the reactive gas at one of the at least two sputter sources being oxygen, the reactive gas at the other of the at least two sputter sources being hydrogen.
Two or more than two of the addressed variants of the methods according to the invention may be combined if they are not contradictory.
Under a first approach, the object outlined above is further resolved according to the invention by a sputter coating apparatus for substrates with two opposed two-dimensionally extended surfaces comprising
In an embodiment of the apparatus according to the invention the third azimuthal spacing is, with respect to the first axis, radially centered between the first and the second azimuthal spacings.
In an embodiment of the apparatus according to the invention the third azimuthal spacing is, with respect to the first axis, radially aligned with the center line of the ring-locus.
Under a second approach, the object outlined above is also resolved according to the invention by a sputter coating apparatus for substrates with two opposed two-dimensionally extended surfaces comprising:
In one embodiment of the apparatus as just addressed, the third averaged strength is located, with respect to the common axis, radially centered between the first and the second averaged strengths.
In one embodiment of the apparatus as just addressed the third averaged strength is located, with respect to the first axis, radially aligned with the center line of the ring-locus.
An embodiment of the apparatus under the first approach comprises additionally
An embodiment of the just addressed embodiment of the apparatus according to the invention comprises a third averaged magnetron magnetic field strength over the sputter surface and over a third azimuthal spacing between the first and the second magnet arrangements located, with respect to the first axis, radially between the first and the second azimuthal spacings and being weaker than the second averaged magnetic field strength.
In an embodiment of the just addressed embodiment of the apparatus according to the invention, the third averaged magnetron field strength is, with respect to the first axis, radially between the first averaged magnetron field strength and the second averaged magnetron field strength.
Additionally, or alternatively to the embodiment of the apparatus as just addressed, in an embodiment of the apparatus according to the invention the third averaged magnetron field strength is, with respect to the first axis, radially aligned with the center line of the ring-locus.
In one embodiment of the apparatus according to the invention, the sputter surface in new state extends along a sputter surface plane and magnet pole surfaces of said magnetron magnet arrangement extend along a magnet arrangement plane the sputter surface plane and the magnet arrangement plane intersecting at an angle α of
0°<α≤20°.
In one embodiment of the apparatus according to the invention the sputter surface in new state extends along a sputter surface plane and a substrate aligned with the sputter source extends along a substrate plane, the sputter surface plane and the substrate plane intersecting at an angle α of
0°<α≤20°.
In one embodiment of the apparatus according to the invention the target backside extends along a backside plane and magnet pole surfaces of the magnetron magnet arrangement extend along a magnet arrangement plane, the backside plane and the magnet arrangement plane intersecting at an angle α of
0°<α≤20°.
In one embodiment of the apparatus according to the invention the target backside extends along a backside plane and a substrate aligned with the sputter source extends along a substrate plane, the backside plane and the substrate plane intersecting at an angle α of
0°<α≤20°.
In one embodiment of the apparatus according to the invention the sputter surface in new state extends along a sputter surface plane and a target backside extends along a backside plane, the backside plane and the sputter surface plane intersecting at an angle α of
0°<α≤20°.
In one embodiment of the apparatus according to the invention a substrate aligned with the sputter source extends along a substrate plane and magnet pole surfaces of said magnetron magnet arrangement extend along a magnet arrangement plane, the substrate plane and the magnet arrangement plane intersecting at an angle α of
0°<α≤20°.
In one embodiment of the apparatus according to the invention the addressed planes intersect along a line perpendicular to a plane containing the first axis and the target center.
In one embodiment of the apparatus according to the invention there is valid:
0°<α≤10°.
In one embodiment of the apparatus according to the invention the first magnet arrangement defines a loop, referring to the angular position with respect to the target center and with the outwards radial direction from the first axis to said target center as angel zero, as follows:
In one embodiment of the apparatus according to the invention the target center resides between the loop defined by the first magnet arrangement and the second magnet arrangement, nested in the addressed loop.
In one embodiment of the apparatus according to the invention the target center is aligned with the center line of the ring-locus.
In one embodiment of the apparatus according to the invention the loop defines a secant with respect to the circular target, departing at an angular range of 30° to 50°.
In one embodiment of the apparatus according to the invention the substrate supports are drivingly rotatable around a respective support central axis.
In one embodiment of the apparatus according to the invention the target is of silicon.
One embodiment of the apparatus according to the invention comprises a gas feed into said housing connected to a gas tank arrangement containing at least one reactive gas.
In one embodiment of the apparatus according to the invention, the addressed gas tank arrangement contains at least one of oxygen and of hydrogen.
One embodiment of the apparatus according to the invention comprises at least two of the addressed sputter sources.
One or more than one of the addressed embodiments may be combined if not contractionary.
The invention shall now further be exemplified with the help of figures.
The figures show:
A substrate conveyer 1 within a vacuum recipient 3—also addressed as “housing”—is continuously rotatable—ω1—around a first axis A1, driven by a drive 2. More than one or a multitude of substrate supports 5 is provided on the substrate conveyer 1, the centers C5 of the substrate supports 5 equidistant from the axis A1. The substrate supports 5 are constructed to support or hold respectively substrates 7 having two opposed two-dimensionally extended surfaces 7a and 7b. In the embodiment of
We understand under “a substrate” a single piece but also more than one single piece being simultaneously treated and conveyed on one substrate support 5.
The substrate supports 5 and thus also the substrates 7 are moved along a ring-locus L7 as shown in
Along their rotational path, the substrates 7 on the substrate supports 5 passes at least one substrate treatment station, thereby at least one sputter source 9.
The sputter source 9 comprises a circular target 11 with a target center C11, a target center axis A11.
The target center C11, in top view, may in some embodiments and as shown in
The sputter source 9 further comprises a magnetron magnet arrangement 13 facing and adjacent the backside 11b of the target 11. As shown schematically at 14, the magnetron magnet arrangement is stationary with respect to the vacuum recipient 3.
The target 11 and therewith a target holder 15 is rotatable with respect to the stationary magnetron magnet arrangement 13 around the target center axis A11, driven by a drive 12.
Via a rotation-contact arrangement 16 the target 11 is electrically supplied from a plasma supply source 18. If the target 11 is cooled as by a channel arrangement 20 at along the target holder 15, a liquid cooling medium M is supplied to the target holder 15 via a rotatable flow connection arrangement 22.
In
When the substrate 7 passes the target 11 at a constant angular velocity—ω1—the azimuthal speed va of each area of the substrate 7 is proportional to the radial distance r from the first axis A1. Assuming a predetermined sputter area K on the sputter surface 11a as shown in
According to the invention and under a first approach the azimuthal extent of the area of magnetron plasma is adapted to the azimuthal speed va of different substrate areas with respect to the first axis A1 and to the azimuthal extent a substrate area passes over the sputter surface 11a of the target 11.
To do so and according to
A second azimuthal extent AE2 is generated in an area of the magnetron plasma 25 closer to the inner periphery Pi of the ring-locus L7 than to the outer periphery Po of the ring-locus L7. This second azimuthal extent AE2 is shorter than the first azimuthal extent AE1. According to the embodiment of
The target shall be sputtered off all along its sputter surface, on one hand to improve exploitation of target material, on the other hand—and of predominant importance when performing reactive sputtering—to minimize or even avoid net redeposition of material on the sputter surface 11a.
Therefore, the target 11 is rotated relative to the stationary magnetron arrangement 13 and thus relative to the stationary area of magnetron plasma 25 as of
As rotation of the target around axis A11 does not displace the target center C11 and this center area as well is to be sputtered off, a third azimuthal extent AE3 in the area of magnetron plasma 25 is generated by the magnetron magnet arrangement 13 which is shorter than the second azimuthal area AE2 and thus presents a constriction of the loop of the area of magnetron plasma 25. Thereby and irrespective of the rotation of the target 11, the target center C11 is sputtered off during a time span which is shorter than the time spans the target areas nearer to the peripheries Po and Pi are sputtered off, thus reducing the overall erosion of the target center C11 to become at least similar to the erosion amount nearer to the peripheries Po, Pi.
According to
170°≤Ω≤190°.
Please note that the angle Ω is defined in the target center as origin and at angle value zero in outwards direction of the radial connecting line of the target center C11 and the first axis A1.
Subsequently the area of magnetron plasma 25 bends towards the target center C11, passes over the target center C11 and bends outwards to again propagate along the periphery P11 of the target, back to Ω=0°.
Please note, that according to
Further and with an eye on
An even more accurate effect is achieved, with respect to avoiding thickness variations of the sputter deposited layer on the substrate 7, due to substrate rotation around the first axis A1 and of sputtering the entire sputter surface 11a, if the area of magnetron plasma 25 follows the periphery P11 of the target 11 as a secant 25a, as shown in dash-dotted lines, departing at a range R2 for Ω of
30°≤Ω≤50°.
A first magnet arrangement 27 of the stationary magnetron magnet arrangement 13 defines a closed loop of subsequent pole surfaces PO1 of one magnet polarity. That the magnetron magnet arrangement 13 is, and thus the pole surfaces PO1 are stationary is represented in
The loop as defined by the magnet pole surfaces PO1 of the one magnetic polarity is located following the periphery P11 of the target 11 thereby starting at an angle Ω of 0° up to an angle Ω in the range R1:
170°≤Ω≤190°.
Subsequently the loop of as defined by the magnet pole surfaces PO1 of the first magnet arrangement 27 bends towards the target center C11, passes nearby the target center C11 and bends outwards to again propagate along the periphery P11 of the target back to Ω=0°.
In dash line,
As not shown in
30°≤Ω≤50°.
Up to now and under a first approach of the invention, we have described the stationary area of magnetron plasma 25 and the respective, stationary first magnet arrangement 27 of the magnetron magnet arrangement 13 combined with the rotating target 11 and a continuously rotating substrate conveyer 1, and thus substrates 7, for minimizing thickness variations of the sputter deposited layer and achieving all-over net sputtering of the sputter surface 11a by selectively tailoring the azimuthal extent of the areas of magnetron plasma which are passed by different areas of the substrates, differently spaced from the first axis A1.
A second approach to resolve object as addressed above shall be explained with the help of
The azimuthal extents AE1a to AE3a are at least similar and differences do not suffice to minimize variations of thickness of the sputter deposited layer on the substrates 7 as desired.
Instead of tailoring the course of the looping area of the area of magnetron plasma, as of loop 25 of the embodiment of
In an area of the sputter surface 11a where the substrates 7 pass the target 11 along the azimuthal pass closer to the outer periphery Po of the ring-locus L7 than to the inner periphery Pi of the ring locus, according to the embodiment as shown in
In an area where the substrates 7 pass the target 11 along the azimuthal pass AE2 closer to the inner periphery Pi of the ring-locus L7 than to the outer periphery Po of the ring-locus L7, a second averaged magnetron magnetic field strength H2 is applied. The averaged strength H2 is smaller than the averaged strength H1 as schematically represented by the respective thicknesses of the arrows respectively representing the strengths of the magnetron magnetic field. In the embodiment of
In a third azimuthal pass AE3a along which the substrates 7 pass the target center C11, a third averaged magnetron magnetic field strength H3 is applied, which is smaller than the second averaged strength H2 of the magnetron magnetic field.
Here again we mention, that the target canter C11 needs not necessarily be aligned with the center line CL7 of the ring-locus L7, as shown in the embodiment of
Further the third azimuthal pass AE3a needs not necessarily be centered between the azimuthal passes AE1a and AE2a as shown in the embodiment of
As perfectly known to the artisan skilled in magnetron art, magnetron magnetic fields of the different strength H1 to H3 are realized by providing at the magnetron magnet arrangement 13 a number of magnetic pole surfaces which respectively vary along the first and/or second magnet arrangements of the magnetron magnet arrangement 13 and/or by varying the strength of magnets along the first and/or second magnet arrangements.
It is absolutely possible to combine the approach according to the embodiment of
The substrates 7 are in one embodiment and as exemplified in the figures circular and in one embodiment rotated—ω7—around respective substrate central axes A7 located along the center line CL7, at least during exposure to the sputter surface 11a of the target 11 by a drive 19 and as schematically shown in
As perfectly known to the skilled artisan in magnetron art, the magnet pole surfaces PO1, PO2 may be realized by at least two permanent magnet arrangements connected in series and linked by a yoke arrangement or are realized by surfaces of pole shoes connected to one or more than one (in series) permanent magnets or by combining such approaches.
The deposition rate of sputtered material, possibly reacted with a reactive gas, is influenced by at least one of
Therefore fine tuning of the deposition rate distribution may be performed by selectively varying one or more than one of the addressed spacings at the sputter source 9 and/or between the respective parts of the sputter source 9 and the substrates 7 aligned with the sputter source 9 by the rotation—ω1—around the first axis A1.
The sputter surface 11a of the target 11 in a new state, i.e. yet un-sputtered, extends along a sputter surface plane Pss. The magnetic pole surfaces PO1, PO2 of the magnetron magnet arrangement 13, schematically shown in
The sputter surface plane PSS and the magnet arrangement plane Pm may be arranged to mutually intersect with an angle α1, selected to fine tune the thickness homogeneity of the layer deposited on the substrates 7 as well as net sputtering of the overall sputter surface 11a.
A substrate 7, when aligned with the sputter source 9, extends along a substrate plane Ps.
The sputter surface plane PSS and the substrate plane PS may be arranged to mutually intersect with an angle α2, selected to fine tune the thickness homogeneity of the layer deposited on the substrates 7 as well as net sputtering of the overall sputter surface 11a.
The backside 11b of the target 11 extends along a backside plane Pbs.
The backside plane Pbs and the magnet arrangement plane Pm may be arranged to mutually intersect with an angle α3, selected to fine tune the thickness homogeneity of the layer deposited on the substrates 7 as well as net sputtering of the overall sputter surface 11a.
The backside plane Pbs and the substrate plane PS may be arranged to mutually intersect with an angle α4, selected to fine tune the thickness homogeneity of the layer deposited on the substrates 7 as well as net sputtering of the overall sputter surface 11a.
The backside plane Pbs and the sputter surface plane PSS may be arranged to mutually intersect with an angle α5, selected to fine tune the thickness homogeneity of the layer deposited on the substrates 7 as well as net sputtering of the overall sputter surface 11a.
The magnet arrangement planes Pm and the substrate plane PS may be arranged to mutually intersect with an angle α6, selected to fine tune the thickness homogeneity of the layer deposited on the substrates 7 as well as net sputtering of the overall sputter surface 11a.
The mutual tilting of the respectively addressed two planes may be realized in any direction. As has been addressed the thickness variations of the material layer deposited on the substrates 7 are caused by the different radial spacings of substrate areas from the first axis A1.
To perform fine tuning in radial direction, with respect to the first axis A1, the addressed tiltings of the respective two planes is, in one embodiment, provided so that the respective intersection lines IL of the addressed two planes is perpendicular to a plane Pα (
The addressed mutual tiltings of the respective pair of planes with tilting angles α1 to α6 are selected in a range of
0°<α≤10°.
In one variant of the method or embodiment of the apparatus according to the invention, the material of the target 11 is silicon. In view of the fact, that silicon is a relatively low-cost material, optimum exploitation of the target material is of secondary importance, of primary importance is that the complete sputter surface 11a of the target 11 is net sputtered off.
This is especially evident if magnetron sputtering is performed in an atmosphere containing at least one reactive gas and coating material is deposited on the substrates 7 which comprises target material reacted with one or more than one reactive gas, thus a material which is different from the target material. Net redeposition of coating material on the sputter surface 11a may be said target poisoning and is minimized or even avoided by the methods and apparatus according to the invention.
In
According to the schematic and simplified top view of
In one embodiment/variant of the invention the at least two sputter source 9a, 9b, both realized according to the invention, have respective targets 11 of silicon. One of the at least two sputter sources, e.g. source 9a according to
Number | Date | Country | Kind |
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01620/19 | Dec 2019 | CH | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2020/082850 | 11/20/2020 | WO |